XR2981______________________________________

3.3V~5V Input 24W Output Step-up DC/DC Converter
GENERAL DESCRIPTIONFEATURES

The XR2981 is a high frequency, highefficiency DC to DC converter with an
integrated 12A, 25mΩ power switch
capable of providing an output voltage up
to 24V. The fixed 600KHz allows the useof small external inductions andcapacitors and provides fast transient
response. It integrates Soft start, Comp,.
only need few components outside.
It can output 6V 3.5A、9V 2A when 3.3VBattery input and output 6V 4.5A、9V 3A
when 3.6V Battery input at good heatdissipation condition


2.7V to 5.5V input voltage Range
Efficiency up to 96%
24V Boost converter with 12A switch
current Limit
600KHz fixed Switching Frequency
Integrated soft-start
Thermal Shutdown
Under voltage Lockout
Support external LDO auxiliary power
supply8-Pin SOP-PP Package

APPLICATIONS
Portable Audio Amplifier Power Supply
Power Bank
QC 2.0/Type C
Wireless Charger
POS Printer Power Supply
Small Motor Power Supply

L 2.2uH 10A

D20V 5A

Vin 3.3V~4.2V

3,4Cby
1uF
16V

Cin

470uF
6.3V

522uF
10V
7,8

VDD

SW

ENFB

Vout 6V 3.5A

1,2R138K

Cout

R2
10K

22uF
10V

6

GND/EPAD

Figure 1. Typical Application Circuit1（for Single cell Li-Battery)
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Rev 0. 5470uF
16V

XR2981_______________________________________________________________________________________

Figure 2. Typical Application Circuit2（for Dual cell Li-Battery)

ORDERING INFORMATIONPARTNUMBER

TEMP RANGESWICHINGFREQUENCYOUTPUT
VOLTAGE (V)ILIM (A)PACKAGEPINS

XR2981-40°C to 85°C

600KHZADJ

12SOP-PP

8

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Rev0.5XR2981_______________________________________________________________________________________PIN CONFIGURATION

Figure 3. PIN Configuration

PIN DESCRIPTIONPINNUMBER

PIN
NAME

1,2SW

Switch pin

3

PVDD

Input power supply pin, please connect with Cin close asp

4

AVDD

Boost IC Logic power supply pin，if far from Cin, please add one 1uF MLCC close asp

5EN

Shutdown control input., Connect this pin to logic high level to enable the device

6FBFeedback pin

7AGND

Analog ground

8

PGND

Power ground

EPAD

PGND

Please connect with PGND & AGND by mass metal for Low Rdson 、High efficiency &Good heat dissipation

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PIN DESCRIPTION-3-

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Rev0.5XR2981_______________________________________________________________________________________ABSOLUTE MAXIMUM RATINGS(Note: Do not exceed these limits to prevent damage to the device. Exposure to absolute maximum rating
conditions for long periods may affect device reliability.)
PARAMETER

VALUE

UNIT

Supply Voltage VIN-0.3 to 6.5

VFB, EN Voltage-0.3 to 6.5

VSW Voltage
Operating Ambient Temperature-0.3 to 26VV-40 to 85°C

Maximum Junction Temperature

150°C-55 to 150°C

300°C

Storage Temperature
Lead Temperature (Soldering, 10 sec)ELECTRICAL CHARACTERISTICS(VIN = 3.6V, TA= 25C unless otherwise specified)
PARAMETERSYMBOLTEST CONDITIONSMINTYPMAXUNIT

5.5

VInput Voltage Range

VIN

2.7

Boost output voltage range

Vout

24

UVLO Low Threshold

VUVLOL

2.6

V

UVLO High Threshold

VUVLOH

3.2

V

Operating Supply Current

V

140

VFB =1.5V，EN=Vin, ILoad =0
ISUPPLY

Shutdown Supply CurrentµA
VEN =0V, VIN =3.6V

1Regulated Feedback
Voltage

VFB

1.21 1.24

Peak Inductor Current

IPEAK

12Oscillator Frequency

FOSC

400

Rds(ON) of N-channel FET

ISW =1A

Enable Threshold

VIN = 2.7V to 5.5V

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0.3
-0.1

VEN = 0V, VSW = 0V or 5V, VIN = 5V-4-1V
A

800

25

Enable Leakage Current
SW Leakage Current

600

1.27

KHzmΩ

1.5

V

0.1

µA

1

uA

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Rev0.5XR2981__________________________________________________________________

EN_____________________
PVDD

AVDD

UVLO

OCP

OTP
SW

OSC/600KHz
Current AMP

FBControl
Logic+EA-

1.24V

CMP+
Bandgap
reference

XR2981
Current AMP

SLOPE+AGND

PGND

Figure 4. Functional Block Diagram

FUNCTIONAL DESCRIPTION
The input for it is the feedback voltage on the FB
pin, the voltage on the internal resistor divider. It is
compared with the internal reference voltage togenerate an accurate and stable output voltage.

NORMAL OPERATIONThe boost converter is designed for output
voltage up to 24V with a 12A/24V power MOSFET.
The low Rdson of the internal power switches
enables better power efficiency. The chip, which
operates in a current mode scheme with constantfrequency 600KHz. It operates with Pulse With
Modulation(PWM). To avoid the inrush current
during power up, soft start circuit is integrated in thechip.

CYCLE BY CYCLE CURRENT LIMIT
The peak current of the NMOS switch is also
sensed to limit the maximum current flowing
through the switch and the inductor. The typicalpeak current limit is set to exceed 12A.

The controller circuit of the device is based on a
fixed frequency multiple feedback controller
topology. Input voltage, output voltage, and voltagedrop on the NMOS switch are monitored andfeedback to the regulator. So changes in theoperating conditions of the converter directly affectthe duty cycle and must not take the indirect andslow way through the control loop and the error
amplifier. The control loop, determined by the error
amplifier, only has to handle small signal errors.
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UNDERVOLTAGE LOCKOUT (UVLO)
Under voltage lockout prevents operation of thedevice at input voltages below typical 2.6V when
the input voltage is falling. When the input voltage isbelow the under voltage threshold, the device isshut down and the internal switch FETs are turned
off. If the input voltage rises by under voltage
lockout hysteresis(3.2V), the IC restarts.

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Rev0.5XR2981__________________________________________________________________

THERMAL SHUTDOWN_____________________

threshold is 150℃ .When the thermal shutdown istriggered the device stops switching until theA thermal shutdown is implemented to prevent
damages due to excessive heat and power
dissipation. Typically the thermal shutdown

temperature falls below typically 136 ℃ .Then thedevice starts switching again.

APPLICATION INFORMATIONINDUCTOR SELECTION
In normal operation, the inductor maintains continuous current to the output. The inductor current has
a ripple that is dependent on the inductance value. The high inductance reduces the ripple current.
Selected inductor by actual application:
Manufa Part Number Inductancecturer(uH)
WURTH

74439358022

Dimensions
L*W*H(mm3)

IdIsat8.8*8.3*7.8

13A30A

11*10*3.8

10A

28A

10.9*10*9.3

16.5A

22A

7.3*6.6*4.8

7.5A

14A

6.9*7.0*3.8

9A

13A

2.2

3.7

2.2

6.5

2.2

4.6

2.2

11.2

2.2

11.4

SPM6530T

2.2

17

7.1*6.5*3

8.4A

VLP6045
LT2.2

20

6*6*4.5

6.4A

74437368022
7443330220
74437349022
744311220
TDKDRC max(mOhms)

Table 1. Recommend Surface Mount Inductors

Notes：Please select inductor according to I in. The IL need to be 1.5~2*I in. For getting higher efficiency, need touse low DRC inductors.

INPUT CAPACITOR SELECTION
The input capacitor reduces input voltage ripple to the converter, low ESR ceramic capacitor is highly
recommended. For audio amplifier applications, A 22uF ceramic capacitor & 470uF E-cap is needed. low ESR
tantalum capacitor is recommended for good ripple performance & dynamic response , The input capacitor
should be placed as close as possible to VIN and GND.

OUTPUT CAPACITOR SELECTION
A low ESR output capacitor is required in order to maintain low output voltage ripple. In the case of ceramic
output capacitors, capacitor ESR is very small and does not contribute to the ripple, so a lower capacitancevalue is acceptable when ceramic capacitors are used. For audio amplifier applications, A 22uF ceramic
capacitor & 470uF E-cap is needed. low ESR tantalum capacitor is recommended for good ripple performance &dynamic response .
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Rev0.5XR2981_______________________________________________________________________________________OUTPUT VOLTAGE PROGRAMMING
In the adjustable version, the output voltage is set by a resistive divider according to the following equation:

Typically choose R2=10K and determine R1 from the following equation:

DIODE SELECTION
According to max Iout

and max Vout, you can select suitable diode. Normally we select

diode

If=(1.5~2)*Ioutmax and VR=(1.5~2)*Voutmax. For high efficiency，suggest that you select low Vf Schottky
diode.
For example, 3.3V~4.2Vin 6V 3.5Aout, you can select SS12P31.
For common application, you can select SS34、 SS54 according to Ioutmax

LDO SELECTION
For Typical Application Circuit2, you need to selecthigher) .Iout>=100mA.Output voltage is preferred to set 4.2V~4.5V.

LDO--Input

voltagerange

4V~15V(orLDO need enough input & output capacity ,please select suitable external parts and layout them according toLDO‘s datasheet.

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Rev0.5XR2981_______________________________________________________________________________________LAYOUT CONSIDERATIONS
1：The input capacitor, output capacitor, and the inductor should be placed as close as possible to the IC. tokeep resistance very low and the switching loop very small for EMI performance
2：The FB pin connection should be made as close to the load as possible so that the voltage at the load isthe expected regulated value. and place FB network far from Switching node.
3：Please make sure that the big current circuits are board and short to reduce the circuit Rdson , All groundconnection must be tied together. Use a broad ground plane to establish the lowest resistance possible between
all connections to achieve the best thermal and noise performance.
4: The switch node connection should be low resistance to reduce power losses.
5:The heavy copper board in big current output is recommended for high efficiency & good heat dissipation.
L 2.2uH 10A

D
20V 5AVin 3.3V~4.2V

3,4
Cby
1uF
16V

Cin

470uF
6.3V

VDDSW

R138K

Switching Loop1522uF
10V
7,8ENVout 6V 3.5A

1,2FB6Switching
Loop2 R2
10K

Cout

22uF
10V

470uF
16V

GND/EPAD

PCB LAYOUT GUIDETOP LAYER
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Rev0.5XR2981_______________________________________________________________________________________TYPICAL PERFORMANCE CHARACTERISTICS(L=2.2uH-Wurth, Cin or Cout=22uF MLCC+470uF Ecap; D=SS12P31, if not mentioned)

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Rev0.5XR2981_______________________________________________________________________________________

Note: Efficiency data is based on demo test at 20℃. If work at big current for long time,maybe thermal shutdown. its load capacity is related with heat dissipation conditions.

3.6Vin9Vout 50mA Switching

3.6Vin9Vout 1A Switching

3.6Vin12Vout 50mA Switching

3.6Vin12Vout 200mA Switching

3.6Vin12Vout 1A Switching
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Rev0.5XR2981__________________________________________________________________

9Vout Startup from Vin

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9Vout Startup from EN- 11 -

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Rev0.5XR2981_______________________________________________________________________________________

PACKAGE OUTLINE
SOP8-PP PACKAGE OUTLINE AND DIMENSIONSSYMBOL

A
A1
A2
BCDE
E1eLFGDimension in Dimension inMillimeters
InchesMINMAXMINMAX
1.35
1.75 0.053 0.069
0.100 0.250 0.004 0.010
1.350 1.550 0.053 0.061
0.330 0.510 0.013 0.020
0.190 0.250 0.007 0.010
4.700 5.100 0.185 0.201
3.800 4.000 0.150 0.157
5.800 6.300 0.228 0.248
1.27 TYP
0.050 TYP
0.400 1.270 0.016 0.050
0o8o0o8o2.26
2.56 0.089 0.101
3.15
3.45 0.124 0.136

In order to increase the driver current capability of XR2981 and improve thetemperature of package, Please ensure Epad and enough ground PCB to releaseenergy.

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